71 INSECTS 



AND DISEASES 



That is why we add humus, why we fertilize, why 

 we cultivate, and why we take note of our plants 

 whUe growing. Only in this way can we supply 

 their wants. 



Weeds spread diseases and we should be 

 ashamed of them. Not only are they usually 

 favorable to the growth of insects, scales and 

 blights, but some kinds of weeds actually breed 

 these parasites. Moreover, they rob the soil 

 of nourishment during the dry, hot spells, thus 

 bringing about various kinds of rots and mil- 

 dews. And now it is supposed that they give 

 out a kind of poison, or excrement, which ren- 

 ders the soil unfit for crops. All this shows the 

 necessity of clean cultivation if we would help, 

 our crops to resist both insects and diseases. 



